5G Internet of Things Data Delivery

ABSTRACT

A wireless transmit/receive unit (WTRU) may establish one or more protocol data unit (PDU) sessions via a radio access network (RAN) node. The WTRU may transition to an inactive state. The WTRU may send a connection resume message to a RAN node that indicates a request to resume the established plurality of PDU sessions via the RAN node. The WTRU may receive a message from the RAN node. For example, the RAN node may send a message indicating a subset of the plurality of PDU sessions that are available upon resuming a connection with the RAN node. The WTRU may deactivate at least one established PDU session of the plurality of PDU sessions based on the received message from the RAN node that indicates at least one established PDU session not being included in the subset of the plurality of PDU sessions that are available.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional ApplicationSerial No. 62/572,127 filed Oct. 13, 2017, the contents of which areincorporated by reference herein.

BACKGROUND

Mobile communications using wireless communication continue to evolve. Afifth generation or Next Gen (NG) may be referred to as 5G. A previousgeneration (e.g., legacy generation) of mobile communication may befourth generation (4G) long term evolution (LTE).

SUMMARY

A wireless transmit/receive unit (WTRU) may establish one or moreprotocol data unit (PDU) sessions via a radio access network (RAN) node.The WTRU may transition to an inactive state, e.g., after establishingone or more PDU sessions via a RAN node. The WTRU may send a connectionresume message to the RAN node from the inactive state. The connectionresume message may indicate a request to resume the establishedplurality of PDU sessions via the RAN node. The connection resumemessage may be included in a radio resource control (RRC) message.

The WTRU may receive a message from the RAN node. In examples, thereceived message from RAN node may indicate a subset of the plurality ofPDU sessions that are available upon resuming a connection with the RANnode. In examples, the received message may indicate a plurality of PDUsession IDs that are available upon resuming the connection with the RANnode. The message (e.g., received from the RAN node) may be included ina RRC message.

The WTRU may deactivate (e.g., upon receiving the message from the RAN)at least one established PDU session of the plurality of PDU sessionsbased on the at least one established PDU session not being included inthe subset of the plurality of PDU sessions that are available asindicated in the received message from the RAN node.

In examples, when the WTRU deactivates the at least one established PDUsession, the WTRU may perform a new registration procedure via anotherRAN node (e.g., a new RAN node). The another RAN node may differ fromthe RAN node that the WTRU established one or more PDU sessions with. Inexamples, the another RAN node (e.g., the new RAN node) may be the sameas the RAN node that the WTRU established one or more PDU sessions with.

In examples, when the WTRU deactivates the at least one established PDUsession, the WTRU may be configured to release (e.g., locally release)and/or remove one or more user plane (UP) resources associated with theat least one established PDU session. For example, locally releasing theone or more UP resources associated with the at least one establishedPDU session may include deactivating one or more data radio bearers(DRBs) associated with the at least one established PDU session.

Networks may be optimized for the Internet of Things (IoT) datadelivery. For example, an access and mobility management function (AMF)may make paging strategies. The paging strategies may be based on adownlink data indication from a session management function (SMF). Theindication may be sent in a non-access stratum (NAS) message. Forexample, an AMF may determine to release a NAS connection, which may bebased on an indication from a SMF and/or a WTRU. For example, a WTRUand/or a network may switch data delivery from a user plane to a controlplane. For example, a WTRU may synchronize an internal list of activePDU session with a RAN. This synchronization may be done using a PDUsession ID(s) maintained by a SMF. For example, a WTRU and/or a networkmay determine to maintain a serving RAN. This determination may be basedthe state of the WTRU and/or the amount of data that the WTRU maydeliver.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a system diagram illustrating an example communicationssystem in which one or more disclosed embodiments may be implemented.

FIG. 1B is a system diagram illustrating an example wirelesstransmit/receive unit (WTRU) that may be used within the communicationssystem illustrated in FIG. 1A according to an embodiment.

FIG. 10 is a system diagram illustrating an example radio access network(RAN) and an example core network (CN) that may be used within thecommunications system illustrated in FIG. 1A according to an embodiment.

FIG. 1D is a system diagram illustrating a further example RAN and afurther example CN that may be used within the communications systemillustrated in FIG. 1A according to an embodiment.

FIG. 2A illustrates an example model of a 5G/NG network.

FIG. 2B illustrates an example service request procedure.

FIG. 3 illustrates an example control plane internet of things (IoT)optimization.

FIG. 4 illustrates an example user plane suspension procedure.

FIG. 5 illustrates an example user plane resume procedure.

FIG. 6 illustrates an example network (NW) initiated service requestprocedure.

FIG. 7 illustrates an example non-access stratum (NAS) signalingconnection release based on an indication from a WTRU and/or a SMF.

FIG. 8 illustrates an example NAS signaling connection release based onan indication from a SMF.

FIG. 9 illustrates an example WTRU initiated deactivation of a userplane (UP) connection.

FIG. 10 illustrates an example core network (CN) initiated deactivationof a UP connection.

FIG. 11A illustrates an example protocol data unit (PDU) session contextsynchronization, e.g., during a resume procedure.

FIG. 11B illustrates an example PDU session context synchronization,e.g., after a resume procedure.

FIG. 12 illustrates an example procedure for avoiding a service RANchange and/or N2 path switch.

DETAILED DESCRIPTION

A detailed description of illustrative embodiments will now be describedwith reference to the various Figures. Although this descriptionprovides a detailed example of possible implementations, it should benoted that the details are intended to be exemplary and in no way limitthe scope of the application.

FIG. 1A is a diagram illustrating an example communications system 100in which one or more disclosed embodiments may be implemented. Thecommunications system 100 may be a multiple access system that providescontent, such as voice, data, video, messaging, broadcast, etc., tomultiple wireless users. The communications system 100 may enablemultiple wireless users to access such content through the sharing ofsystem resources, including wireless bandwidth. For example, thecommunications systems 100 may employ one or more channel accessmethods, such as code division multiple access (CDMA), time divisionmultiple access (TDMA), frequency division multiple access (FDMA),orthogonal FDMA (OFDMA), single-carrier FDMA (SC-FDMA), zero-tailunique-word DFT-Spread OFDM (ZT UW DTS-s OFDM), unique word OFDM(UW-OFDM), resource block-filtered OFDM, filter bank multicarrier(FBMC), and the like.

As shown in FIG. 1A, the communications system 100 may include wirelesstransmit/receive units (WTRUs) 102 a, 102 b, 102 c, 102 d, a RAN104/113, a CN 106/115, a public switched telephone network (PSTN) 108,the Internet 110, and other networks 112, though it will be appreciatedthat the disclosed embodiments contemplate any number of WTRUs, basestations, networks, and/or network elements. Each of the WTRUs 102 a,102 b, 102 c, 102 d may be any type of device configured to operateand/or communicate in a wireless environment. By way of example, theWTRUs 102 a, 102 b, 102 c, 102 d, any of which may be referred to as a“station” and/or a “STA”, may be configured to transmit and/or receivewireless signals and may include a user equipment (UE), a mobilestation, a fixed or mobile subscriber unit, a subscription-based unit, apager, a cellular telephone, a personal digital assistant (PDA), asmartphone, a laptop, a netbook, a personal computer, a wireless sensor,a hotspot or Mi-Fi device, an Internet of Things (IoT) device, a watchor other wearable, a head-mounted display (HMD), a vehicle, a drone, amedical device and applications (e.g., remote surgery), an industrialdevice and applications (e.g., a robot and/or other wireless devicesoperating in an industrial and/or an automated processing chaincontexts), a consumer electronics device, a device operating oncommercial and/or industrial wireless networks, and the like. Any of theWTRUs 102 a, 102 b, 102 c and 102 d may be interchangeably referred toas a UE.

The communications systems 100 may also include a base station 114 aand/or a base station 114 b. Each of the base stations 114 a, 114 b maybe any type of device configured to wirelessly interface with at leastone of the WTRUs 102 a, 102 b, 102 c, 102 d to facilitate access to oneor more communication networks, such as the CN 106/115, the Internet110, and/or the other networks 112. By way of example, the base stations114 a, 114 b may be a base transceiver station (BTS), a Node-B, an eNodeB, a Home Node B, a Home eNode B, a gNB, a NR NodeB, a site controller,an access point (AP), a wireless router, and the like. While the basestations 114 a, 114 b are each depicted as a single element, it will beappreciated that the base stations 114 a, 114 b may include any numberof interconnected base stations and/or network elements.

The base station 114 a may be part of the RAN 104/113, which may alsoinclude other base stations and/or network elements (not shown), such asa base station controller (BSC), a radio network controller (RNC), relaynodes, etc. The base station 114 a and/or the base station 114 b may beconfigured to transmit and/or receive wireless signals on one or morecarrier frequencies, which may be referred to as a cell (not shown).These frequencies may be in licensed spectrum, unlicensed spectrum, or acombination of licensed and unlicensed spectrum. A cell may providecoverage for a wireless service to a specific geographical area that maybe relatively fixed or that may change over time. The cell may furtherbe divided into cell sectors. For example, the cell associated with thebase station 114 a may be divided into three sectors. Thus, in oneembodiment, the base station 114 a may include three transceivers, i.e.,one for each sector of the cell. In an embodiment, the base station 114a may employ multiple-input multiple output (MIMO) technology and mayutilize multiple transceivers for each sector of the cell. For example,beamforming may be used to transmit and/or receive signals in desiredspatial directions.

The base stations 114 a, 114 b may communicate with one or more of theWTRUs 102 a, 102 b, 102 c, 102 d over an air interface 116, which may beany suitable wireless communication link (e.g., radio frequency (RF),microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet(UV), visible light, etc.). The air interface 116 may be establishedusing any suitable radio access technology (RAT).

More specifically, as noted above, the communications system 100 may bea multiple access system and may employ one or more channel accessschemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and the like. Forexample, the base station 114 a in the RAN 104/113 and the WTRUs 102 a,102 b, 102 c may implement a radio technology such as Universal MobileTelecommunications System (UMTS) Terrestrial Radio Access (UTRA), whichmay establish the air interface 115/116/117 using wideband CDMA (WCDMA).WCDMA may include communication protocols such as High-Speed PacketAccess (HSPA) and/or Evolved HSPA (HSPA+). HSPA may include High-SpeedDownlink (DL) Packet Access (HSDPA) and/or High-Speed UL Packet Access(HSUPA).

In an embodiment, the base station 114 a and the WTRUs 102 a, 102 b, 102c may implement a radio technology such as Evolved UMTS TerrestrialRadio Access (E-UTRA), which may establish the air interface 116 usingLong Term Evolution (LTE) and/or LTE-Advanced (LTE-A) and/orLTE-Advanced Pro (LTE-A Pro).

In an embodiment, the base station 114 a and the WTRUs 102 a, 102 b, 102c may implement a radio technology such as NR Radio Access, which mayestablish the air interface 116 using New Radio (NR).

In an embodiment, the base station 114 a and the WTRUs 102 a, 102 b, 102c may implement multiple radio access technologies. For example, thebase station 114 a and the WTRUs 102 a, 102 b, 102 c may implement LTEradio access and NR radio access together, for instance using dualconnectivity (DC) principles. Thus, the air interface utilized by WTRUs102 a, 102 b, 102 c may be characterized by multiple types of radioaccess technologies and/or transmissions sent to/from multiple types ofbase stations (e.g., a eNB and a gNB).

In other embodiments, the base station 114 a and the WTRUs 102 a, 102 b,102 c may implement radio technologies such as IEEE 802.11 (i.e.,Wireless Fidelity (WiFi), IEEE 802.16 (i.e., Worldwide Interoperabilityfor Microwave Access (WiMAX)), CDMA2000, CDMA2000 1×, CDMA2000 EV-DO,Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), InterimStandard 856 (IS-856), Global System for Mobile communications (GSM),Enhanced Data rates for GSM Evolution (EDGE), GSM EDGE (GERAN), and thelike.

The base station 114 b in FIG. 1A may be a wireless router, Home Node B,Home eNode B, or access point, for example, and may utilize any suitableRAT for facilitating wireless connectivity in a localized area, such asa place of business, a home, a vehicle, a campus, an industrialfacility, an air corridor (e.g., for use by drones), a roadway, and thelike. In one embodiment, the base station 114 b and the WTRUs 102 c, 102d may implement a radio technology such as IEEE 802.11 to establish awireless local area network (WLAN). In an embodiment, the base station114 b and the WTRUs 102 c, 102 d may implement a radio technology suchas IEEE 802.15 to establish a wireless personal area network (WPAN). Inyet another embodiment, the base station 114 b and the WTRUs 102 c, 102d may utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE,LTE-A, LTE-A Pro, NR etc.) to establish a picocell or femtocell. Asshown in FIG. 1A, the base station 114 b may have a direct connection tothe Internet 110. Thus, the base station 114 b may not be required toaccess the Internet 110 via the CN 106/115.

The RAN 104/113 may be in communication with the CN 106/115, which maybe any type of network configured to provide voice, data, applications,and/or voice over internet protocol (VoIP) services to one or more ofthe WTRUs 102 a, 102 b, 102 c, 102 d. The data may have varying qualityof service (QoS) requirements, such as differing throughputrequirements, latency requirements, error tolerance requirements,reliability requirements, data throughput requirements, mobilityrequirements, and the like. The CN 106/115 may provide call control,billing services, mobile location-based services, pre-paid calling,Internet connectivity, video distribution, etc., and/or performhigh-level security functions, such as user authentication. Although notshown in FIG. 1A, it will be appreciated that the RAN 104/113 and/or theCN 106/115 may be in direct or indirect communication with other RANsthat employ the same RAT as the RAN 104/113 or a different RAT. Forexample, in addition to being connected to the RAN 104/113, which may beutilizing a NR radio technology, the CN 106/115 may also be incommunication with another RAN (not shown) employing a GSM, UMTS, CDMA2000, WiMAX, E-UTRA, or WiFi radio technology.

The CN 106/115 may also serve as a gateway for the WTRUs 102 a, 102 b,102 c, 102 d to access the PSTN 108, the Internet 110, and/or the othernetworks 112. The PSTN 108 may include circuit-switched telephonenetworks that provide plain old telephone service (POTS). The Internet110 may include a global system of interconnected computer networks anddevices that use common communication protocols, such as thetransmission control protocol (TCP), user datagram protocol (UDP) and/orthe internet protocol (IP) in the TCP/IP internet protocol suite. Thenetworks 112 may include wired and/or wireless communications networksowned and/or operated by other service providers. For example, thenetworks 112 may include another CN connected to one or more RANs, whichmay employ the same RAT as the RAN 104/113 or a different RAT.

Some or all of the WTRUs 102 a, 102 b, 102 c, 102 d in thecommunications system 100 may include multi-mode capabilities (e.g., theWTRUs 102 a, 102 b, 102 c, 102 d may include multiple transceivers forcommunicating with different wireless networks over different wirelesslinks). For example, the WTRU 102 c shown in FIG. 1A may be configuredto communicate with the base station 114 a, which may employ acellular-based radio technology, and with the base station 114 b, whichmay employ an IEEE 802 radio technology.

FIG. 1B is a system diagram illustrating an example WTRU 102. As shownin FIG. 1B, the WTRU 102 may include a processor 118, a transceiver 120,a transmit/receive element 122, a speaker/microphone 124, a keypad 126,a display/touchpad 128, non-removable memory 130, removable memory 132,a power source 134, a global positioning system (GPS) chipset 136,and/or other peripherals 138, among others. It will be appreciated thatthe WTRU 102 may include any sub-combination of the foregoing elementswhile remaining consistent with an embodiment.

The processor 118 may be a general purpose processor, a special purposeprocessor, a conventional processor, a digital signal processor (DSP), aplurality of microprocessors, one or more microprocessors in associationwith a DSP core, a controller, a microcontroller, Application SpecificIntegrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs)circuits, any other type of integrated circuit (IC), a state machine,and the like. The processor 118 may perform signal coding, dataprocessing, power control, input/output processing, and/or any otherfunctionality that enables the WTRU 102 to operate in a wirelessenvironment. The processor 118 may be coupled to the transceiver 120,which may be coupled to the transmit/receive element 122. While FIG. 1Bdepicts the processor 118 and the transceiver 120 as separatecomponents, it will be appreciated that the processor 118 and thetransceiver 120 may be integrated together in an electronic package orchip.

The transmit/receive element 122 may be configured to transmit signalsto, or receive signals from, a base station (e.g., the base station 114a) over the air interface 116. For example, in one embodiment, thetransmit/receive element 122 may be an antenna configured to transmitand/or receive RF signals. In an embodiment, the transmit/receiveelement 122 may be an emitter/detector configured to transmit and/orreceive IR, UV, or visible light signals, for example. In yet anotherembodiment, the transmit/receive element 122 may be configured totransmit and/or receive both RF and light signals. It will beappreciated that the transmit/receive element 122 may be configured totransmit and/or receive any combination of wireless signals.

Although the transmit/receive element 122 is depicted in FIG. 1B as asingle element, the WTRU 102 may include any number of transmit/receiveelements 122. More specifically, the WTRU 102 may employ MIMOtechnology. Thus, in one embodiment, the WTRU 102 may include two ormore transmit/receive elements 122 (e.g., multiple antennas) fortransmitting and receiving wireless signals over the air interface 116.

The transceiver 120 may be configured to modulate the signals that areto be transmitted by the transmit/receive element 122 and to demodulatethe signals that are received by the transmit/receive element 122. Asnoted above, the WTRU 102 may have multi-mode capabilities. Thus, thetransceiver 120 may include multiple transceivers for enabling the WTRU102 to communicate via multiple RATs, such as NR and IEEE 802.11, forexample.

The processor 118 of the WTRU 102 may be coupled to, and may receiveuser input data from, the speaker/microphone 124, the keypad 126, and/orthe display/touchpad 128 (e.g., a liquid crystal display (LCD) displayunit or organic light-emitting diode (OLED) display unit). The processor118 may also output user data to the speaker/microphone 124, the keypad126, and/or the display/touchpad 128. In addition, the processor 118 mayaccess information from, and store data in, any type of suitable memory,such as the non-removable memory 130 and/or the removable memory 132.The non-removable memory 130 may include random-access memory (RAM),read-only memory (ROM), a hard disk, or any other type of memory storagedevice. The removable memory 132 may include a subscriber identitymodule (SIM) card, a memory stick, a secure digital (SD) memory card,and the like. In other embodiments, the processor 118 may accessinformation from, and store data in, memory that is not physicallylocated on the WTRU 102, such as on a server or a home computer (notshown).

The processor 118 may receive power from the power source 134, and maybe configured to distribute and/or control the power to the othercomponents in the WTRU 102. The power source 134 may be any suitabledevice for powering the WTRU 102. For example, the power source 134 mayinclude one or more dry cell batteries (e.g., nickel-cadmium (NiCd),nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion),etc.), solar cells, fuel cells, and the like.

The processor 118 may also be coupled to the GPS chipset 136, which maybe configured to provide location information (e.g., longitude andlatitude) regarding the current location of the WTRU 102. In additionto, or in lieu of, the information from the GPS chipset 136, the WTRU102 may receive location information over the air interface 116 from abase station (e.g., base stations 114 a, 114 b) and/or determine itslocation based on the timing of the signals being received from two ormore nearby base stations. It will be appreciated that the WTRU 102 mayacquire location information by way of any suitablelocation-determination method while remaining consistent with anembodiment.

The processor 118 may further be coupled to other peripherals 138, whichmay include one or more software and/or hardware modules that provideadditional features, functionality and/or wired or wirelessconnectivity. For example, the peripherals 138 may include anaccelerometer, an e-compass, a satellite transceiver, a digital camera(for photographs and/or video), a universal serial bus (USB) port, avibration device, a television transceiver, a hands free headset, aBluetooth® module, a frequency modulated (FM) radio unit, a digitalmusic player, a media player, a video game player module, an Internetbrowser, a Virtual Reality and/or Augmented Reality (VR/AR) device, anactivity tracker, and the like. The peripherals 138 may include one ormore sensors, the sensors may be one or more of a gyroscope, anaccelerometer, a hall effect sensor, a magnetometer, an orientationsensor, a proximity sensor, a temperature sensor, a time sensor; ageolocation sensor; an altimeter, a light sensor, a touch sensor, amagnetometer, a barometer, a gesture sensor, a biometric sensor, and/ora humidity sensor.

The WTRU 102 may include a full duplex radio for which transmission andreception of some or all of the signals (e.g., associated withparticular subframes for both the UL (e.g., for transmission) anddownlink (e.g., for reception) may be concurrent and/or simultaneous.The full duplex radio may include an interference management unit toreduce and or substantially eliminate self-interference via eitherhardware (e.g., a choke) or signal processing via a processor (e.g., aseparate processor (not shown) or via processor 118). In an embodiment,the WRTU 102 may include a half-duplex radio for which transmission andreception of some or all of the signals (e.g., associated withparticular subframes for either the UL (e.g., for transmission) or thedownlink (e.g., for reception)).

FIG. 10 is a system diagram illustrating the RAN 104 and the CN 106according to an embodiment. As noted above, the RAN 104 may employ anE-UTRA radio technology to communicate with the WTRUs 102 a, 102 b, 102c over the air interface 116. The RAN 104 may also be in communicationwith the CN 106.

The RAN 104 may include eNode-Bs 160 a, 160 b, 160 c, though it will beappreciated that the RAN 104 may include any number of eNode-Bs whileremaining consistent with an embodiment. The eNode-Bs 160 a, 160 b, 160c may each include one or more transceivers for communicating with theWTRUs 102 a, 102 b, 102 c over the air interface 116. In one embodiment,the eNode-Bs 160 a, 160 b, 160 c may implement MIMO technology. Thus,the eNode-B 160 a, for example, may use multiple antennas to transmitwireless signals to, and/or receive wireless signals from, the WTRU 102a.

Each of the eNode-Bs 160 a, 160 b, 160 c may be associated with aparticular cell (not shown) and may be configured to handle radioresource management decisions, handover decisions, scheduling of usersin the UL and/or DL, and the like. As shown in FIG. 10, the eNode-Bs 160a, 160 b, 160 c may communicate with one another over an X2 interface.

The CN 106 shown in FIG. 10 may include a mobility management entity(MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN)gateway (or PGW) 166. While each of the foregoing elements are depictedas part of the CN 106, it will be appreciated that any of these elementsmay be owned and/or operated by an entity other than the CN operator.

The MME 162 may be connected to each of the eNode-Bs 162 a, 162 b, 162 cin the RAN 104 via an S1 interface and may serve as a control node. Forexample, the MME 162 may be responsible for authenticating users of theWTRUs 102 a, 102 b, 102 c, bearer activation/deactivation, selecting aparticular serving gateway during an initial attach of the WTRUs 102 a,102 b, 102 c, and the like. The MME 162 may provide a control planefunction for switching between the RAN 104 and other RANs (not shown)that employ other radio technologies, such as GSM and/or WCDMA.

The SGW 164 may be connected to each of the eNode Bs 160 a, 160 b, 160 cin the RAN 104 via the S1 interface. The SGW 164 may generally route andforward user data packets to/from the WTRUs 102 a, 102 b, 102 c. The SGW164 may perform other functions, such as anchoring user planes duringinter-eNode B handovers, triggering paging when DL data is available forthe WTRUs 102 a, 102 b, 102 c, managing and storing contexts of theWTRUs 102 a, 102 b, 102 c, and the like.

The SGW 164 may be connected to the PGW 166, which may provide the WTRUs102 a, 102 b, 102 c with access to packet-switched networks, such as theInternet 110, to facilitate communications between the WTRUs 102 a, 102b, 102 c and IP-enabled devices.

The CN 106 may facilitate communications with other networks. Forexample, the CN 106 may provide the WTRUs 102 a, 102 b, 102 c withaccess to circuit-switched networks, such as the PSTN 108, to facilitatecommunications between the WTRUs 102 a, 102 b, 102 c and traditionalland-line communications devices. For example, the CN 106 may include,or may communicate with, an IP gateway (e.g., an IP multimedia subsystem(IMS) server) that serves as an interface between the CN 106 and thePSTN 108. In addition, the CN 106 may provide the WTRUs 102 a, 102 b,102 c with access to the other networks 112, which may include otherwired and/or wireless networks that are owned and/or operated by otherservice providers.

Although the WTRU is described in FIGS. 1A-1D as a wireless terminal, itis contemplated that in certain representative embodiments that such aterminal may use (e.g., temporarily or permanently) wired communicationinterfaces with the communication network.

In representative embodiments, the other network 112 may be a WLAN.

A WLAN in Infrastructure Basic Service Set (BSS) mode may have an AccessPoint (AP) for the BSS and one or more stations (STAs) associated withthe AP. The AP may have an access or an interface to a DistributionSystem (DS) or another type of wired/wireless network that carriestraffic in to and/or out of the BSS. Traffic to STAs that originatesfrom outside the BSS may arrive through the AP and may be delivered tothe STAs. Traffic originating from STAs to destinations outside the BSSmay be sent to the AP to be delivered to respective destinations.Traffic between STAs within the BSS may be sent through the AP, forexample, where the source STA may send traffic to the AP and the AP maydeliver the traffic to the destination STA. The traffic between STAswithin a BSS may be considered and/or referred to as peer-to-peertraffic. The peer-to-peer traffic may be sent between (e.g., directlybetween) the source and destination STAs with a direct link setup (DLS).In certain representative embodiments, the DLS may use an 802.11e DLS oran 802.11z tunneled DLS (TDLS). A WLAN using an Independent BSS (IBSS)mode may not have an AP, and the STAs (e.g., all of the STAs) within orusing the IBSS may communicate directly with each other. The IBSS modeof communication may sometimes be referred to herein as an “ad-hoc” modeof communication.

When using the 802.11ac infrastructure mode of operation or a similarmode of operations, the AP may transmit a beacon on a fixed channel,such as a primary channel. The primary channel may be a fixed width(e.g., 20 MHz wide bandwidth) or a dynamically set width via signaling.The primary channel may be the operating channel of the BSS and may beused by the STAs to establish a connection with the AP. In certainrepresentative embodiments, Carrier Sense Multiple Access with CollisionAvoidance (CSMA/CA) may be implemented, for example in in 802.11systems. For CSMA/CA, the STAs (e.g., every STA), including the AP, maysense the primary channel. If the primary channel is sensed/detectedand/or determined to be busy by a particular STA, the particular STA mayback off. One STA (e.g., only one station) may transmit at any giventime in a given BSS.

High Throughput (HT) STAs may use a 40 MHz wide channel forcommunication, for example, via a combination of the primary 20 MHzchannel with an adjacent or nonadjacent 20 MHz channel to form a 40 MHzwide channel.

Very High Throughput (VHT) STAs may support 20 MHz, 40 MHz, 80 MHz,and/or 160 MHz wide channels. The 40 MHz, and/or 80 MHz, channels may beformed by combining contiguous 20 MHz channels.

A 160 MHz channel may be formed by combining 8 contiguous 20 MHzchannels, or by combining two non-contiguous 80 MHz channels, which maybe referred to as an 80+80 configuration. For the 80+80 configuration,the data, after channel encoding, may be passed through a segment parserthat may divide the data into two streams. Inverse Fast FourierTransform (IFFT) processing, and time domain processing, may be done oneach stream separately. The streams may be mapped on to the two 80 MHzchannels, and the data may be transmitted by a transmitting STA. At thereceiver of the receiving STA, the above described operation for the80+80 configuration may be reversed, and the combined data may be sentto the Medium Access Control (MAC).

Sub 1 GHz modes of operation are supported by 802.11af and 802.11ah. Thechannel operating bandwidths, and carriers, are reduced in 802.11af and802.11ah relative to those used in 802.11n, and 802.11ac. 802.11afsupports 5 MHz, 10 MHz and 20 MHz bandwidths in the TV White Space(TVWS) spectrum, and 802.11ah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz, and16 MHz bandwidths using non-TVWS spectrum. According to a representativeembodiment, 802.11ah may support Meter Type Control/Machine-TypeCommunications, such as MTC devices in a macro coverage area. MTCdevices may have certain capabilities, for example, limited capabilitiesincluding support for certain and/or limited bandwidths. The MTC devicesmay include a battery with a battery life above a threshold (e.g., tomaintain a very long battery life).

WLAN systems, which may support multiple channels, and channelbandwidths, such as 802.11n, 802.11ac, 802.11af, and 802.11ah, include achannel which may be designated as the primary channel. The primarychannel may have a bandwidth equal to the largest common operatingbandwidth supported by all STAs in the BSS. The bandwidth of the primarychannel may be set and/or limited by a STA, from among all STAs inoperating in a BSS, which supports the smallest bandwidth operatingmode. In the example of 802.11ah, the primary channel may be 1 MHz widefor STAs (e.g., MTC type devices) that support (e.g., only support) a 1MHz mode, even if the AP, and other STAs in the BSS support 2 MHz, 4MHz, 8 MHz, 16 MHz, and/or other channel bandwidth operating modes.Carrier sensing and/or Network Allocation Vector (NAV) settings maydepend on the status of the primary channel. If the primary channel isbusy, for example, due to a STA (which supports only a 1 MHz operatingmode), transmitting to the AP, the entire available frequency bands maybe considered busy even though a majority of the frequency bands remainsidle and may be available.

In the United States, the available frequency bands, which may be usedby 802.11ah, are from 902 MHz to 928 MHz. In Korea, the availablefrequency bands are from 917.5 MHz to 923.5 MHz. In Japan, the availablefrequency bands are from 916.5 MHz to 927.5 MHz. The total bandwidthavailable for 802.11ah is 6 MHz to 26 MHz depending on the country code.

FIG. 1D is a system diagram illustrating the RAN 113 and the CN 115according to an embodiment. As noted above, the RAN 113 may employ an NRradio technology to communicate with the WTRUs 102 a, 102 b, 102 c overthe air interface 116. The RAN 113 may also be in communication with theCN 115.

The RAN 113 may include gNBs 180 a, 180 b, 180 c, though it will beappreciated that the RAN 113 may include any number of gNBs whileremaining consistent with an embodiment. The gNBs 180 a, 180 b, 180 cmay each include one or more transceivers for communicating with theWTRUs 102 a, 102 b, 102 c over the air interface 116. In one embodiment,the gNBs 180 a, 180 b, 180 c may implement MIMO technology. For example,gNBs 180 a, 108 b may utilize beamforming to transmit signals to and/orreceive signals from the gNBs 180 a, 180 b, 180 c. Thus, the gNB 180 a,for example, may use multiple antennas to transmit wireless signals to,and/or receive wireless signals from, the WTRU 102 a. In an embodiment,the gNBs 180 a, 180 b, 180 c may implement carrier aggregationtechnology. For example, the gNB 180 a may transmit multiple componentcarriers to the WTRU 102 a (not shown). A subset of these componentcarriers may be on unlicensed spectrum while the remaining componentcarriers may be on licensed spectrum. In an embodiment, the gNBs 180 a,180 b, 180 c may implement Coordinated Multi-Point (CoMP) technology.For example, WTRU 102 a may receive coordinated transmissions from gNB180 a and gNB 180 b (and/or gNB 180 c).

The WTRUs 102 a, 102 b, 102 c may communicate with gNBs 180 a, 180 b,180 c using transmissions associated with a scalable numerology. Forexample, the OFDM symbol spacing and/or OFDM subcarrier spacing may varyfor different transmissions, different cells, and/or different portionsof the wireless transmission spectrum. The WTRUs 102 a, 102 b, 102 c maycommunicate with gNBs 180 a, 180 b, 180 c using subframe or transmissiontime intervals (TTIs) of various or scalable lengths (e.g., containingvarying number of OFDM symbols and/or lasting varying lengths ofabsolute time).

The gNBs 180 a, 180 b, 180 c may be configured to communicate with theWTRUs 102 a, 102 b, 102 c in a standalone configuration and/or anon-standalone configuration. In the standalone configuration, WTRUs 102a, 102 b, 102 c may communicate with gNBs 180 a, 180 b, 180 c withoutalso accessing other RANs (e.g., such as eNode-Bs 160 a, 160 b, 160 c).In the standalone configuration, WTRUs 102 a, 102 b, 102 c may utilizeone or more of gNBs 180 a, 180 b, 180 c as a mobility anchor point. Inthe standalone configuration, WTRUs 102 a, 102 b, 102 c may communicatewith gNBs 180 a, 180 b, 180 c using signals in an unlicensed band. In anon-standalone configuration WTRUs 102 a, 102 b, 102 c may communicatewith/connect to gNBs 180 a, 180 b, 180 c while also communicatingwith/connecting to another RAN such as eNode-Bs 160 a, 160 b, 160 c. Forexample, WTRUs 102 a, 102 b, 102 c may implement DC principles tocommunicate with one or more gNBs 180 a, 180 b, 180 c and one or moreeNode-Bs 160 a, 160 b, 160 c substantially simultaneously. In thenon-standalone configuration, eNode-Bs 160 a, 160 b, 160 c may serve asa mobility anchor for WTRUs 102 a, 102 b, 102 c and gNBs 180 a, 180 b,180 c may provide additional coverage and/or throughput for servicingWTRUs 102 a, 102 b, 102 c.

Each of the gNBs 180 a, 180 b, 180 c may be associated with a particularcell (not shown) and may be configured to handle radio resourcemanagement decisions, handover decisions, scheduling of users in the ULand/or DL, support of network slicing, dual connectivity, interworkingbetween NR and E-UTRA, routing of user plane data towards User PlaneFunction (UPF) 184 a, 184 b, routing of control plane informationtowards Access and Mobility Management Function (AMF) 182 a, 182 b andthe like. As shown in FIG. 1D, the gNBs 180 a, 180 b, 180 c maycommunicate with one another over an Xn interface.

The CN 115 shown in FIG. 1D may include at least one AMF 182 a, 182 b,at least one UPF 184 a,184 b, at least one Session Management Function(SMF) 183 a, 183 b, and possibly a Data Network (DN) 185 a, 185 b. Whileeach of the foregoing elements are depicted as part of the CN 115, itwill be appreciated that any of these elements may be owned and/oroperated by an entity other than the CN operator.

The AMF 182 a, 182 b may be connected to one or more of the gNBs 180 a,180 b, 180 c in the RAN 113 via an N2 interface and may serve as acontrol node. For example, the AMF 182 a, 182 b may be responsible forauthenticating users of the WTRUs 102 a, 102 b, 102 c, support fornetwork slicing (e.g., handling of different PDU sessions with differentrequirements), selecting a particular SMF 183 a, 183 b, management ofthe registration area, termination of NAS signaling, mobilitymanagement, and the like. Network slicing may be used by the AMF 182 a,182 b in order to customize CN support for WTRUs 102 a, 102 b, 102 cbased on the types of services being utilized WTRUs 102 a, 102 b, 102 c.For example, different network slices may be established for differentuse cases such as services relying on ultra-reliable low latency (URLLC)access, services relying on enhanced massive mobile broadband (eMBB)access, services for machine type communication (MTC) access, and/or thelike. The AMF 162 may provide a control plane function for switchingbetween the RAN 113 and other RANs (not shown) that employ other radiotechnologies, such as LTE, LTE-A, LTE-A Pro, and/or non-3GPP accesstechnologies such as WiFi.

The SMF 183 a, 183 b may be connected to an AMF 182 a, 182 b in the CN115 via an N11 interface. The SMF 183 a, 183 b may also be connected toa UPF 184 a, 184 b in the CN 115 via an N4 interface. The SMF 183 a, 183b may select and control the UPF 184 a, 184 b and configure the routingof traffic through the UPF 184 a, 184 b. The SMF 183 a, 183 b mayperform other functions, such as managing and allocating UE IP address,managing PDU sessions, controlling policy enforcement and QoS, providingdownlink data notifications, and the like. A PDU session type may beIP-based, non-IP based, Ethernet-based, and the like.

The UPF 184 a, 184 b may be connected to one or more of the gNBs 180 a,180 b, 180 c in the RAN 113 via an N3 interface, which may provide theWTRUs 102 a, 102 b, 102 c with access to packet-switched networks, suchas the Internet 110, to facilitate communications between the WTRUs 102a, 102 b, 102 c and IP-enabled devices. The UPF 184, 184 b may performother functions, such as routing and forwarding packets, enforcing userplane policies, supporting multi-homed PDU sessions, handling user planeQoS, buffering downlink packets, providing mobility anchoring, and thelike.

The CN 115 may facilitate communications with other networks. Forexample, the CN 115 may include, or may communicate with, an IP gateway(e.g., an IP multimedia subsystem (IMS) server) that serves as aninterface between the CN 115 and the PSTN 108. In addition, the CN 115may provide the WTRUs 102 a, 102 b, 102 c with access to the othernetworks 112, which may include other wired and/or wireless networksthat are owned and/or operated by other service providers. In oneembodiment, the WTRUs 102 a, 102 b, 102 c may be connected to a localData Network (DN) 185 a, 185 b through the UPF 184 a, 184 b via the N3interface to the UPF 184 a, 184 b and an N6 interface between the UPF184 a, 184 b and the DN 185 a, 185 b.

In view of FIGS. 1A-1D, and the corresponding description of FIGS.1A-1D, one or more, or all, of the functions described herein withregard to one or more of: WTRU 102 a-d, Base Station 114 a-b, eNode-B160 a-c, MME 162, SGW 164, PGW 166, gNB 180 a-c, AMF 182 a-b, UPF 184a-b, SMF 183 a-b, DN 185 a-b, and/or any other device(s) describedherein, may be performed by one or more emulation devices (not shown).The emulation devices may be one or more devices configured to emulateone or more, or all, of the functions described herein. For example, theemulation devices may be used to test other devices and/or to simulatenetwork and/or WTRU functions.

The emulation devices may be designed to implement one or more tests ofother devices in a lab environment and/or in an operator networkenvironment. For example, the one or more emulation devices may performthe one or more, or all, functions while being fully or partiallyimplemented and/or deployed as part of a wired and/or wirelesscommunication network in order to test other devices within thecommunication network. The one or more emulation devices may perform theone or more, or all, functions while being temporarilyimplemented/deployed as part of a wired and/or wireless communicationnetwork. The emulation device may be directly coupled to another devicefor purposes of testing and/or may performing testing using over-the-airwireless communications.

The one or more emulation devices may perform the one or more, includingall, functions while not being implemented/deployed as part of a wiredand/or wireless communication network. For example, the emulationdevices may be utilized in a testing scenario in a testing laboratoryand/or a non-deployed (e.g., testing) wired and/or wirelesscommunication network in order to implement testing of one or morecomponents. The one or more emulation devices may be test equipment.Direct RF coupling and/or wireless communications via RF circuitry(e.g., which may include one or more antennas) may be used by theemulation devices to transmit and/or receive data.

FIG. 2A illustrates an example model architecture for 5G and/or NGnetwork. A RAN may be based on a 5G radio access technology (RAT) and/oran evolved E-UTRA that may connect to a NG core network.

An access control and mobility management function (AMF) may includefunctionality for registration management, connection management,reachability management, mobility management, and/or the like.

A session management function (SMF) may include functionality forsession management, session establishment, session modification, sessionrelease, WTRU IP address allocation, selection and/or control of UPfunction(s), and/or the like.

A user plane function (UPF) may include functionality for packetrouting, packet forwarding, packet inspection, traffic usage reporting,and/or the like.

A WTRU may establish a PDU session(s) for data delivery. For example, aWTRU may establish a PDU session(s) for data delivery after registrationto a network (e.g., 5G network). If, for example, the WTRU is in idlestatus, has mobile originated (MO) data, and/or has mobile terminated(MT) data delivery, the WTRU may perform a service request procedure.The WTRU may perform a service request procedure that may establish auser plane for data delivery. The WTRU and/or network may use the userplane (e.g., delivering up-link/down-link (UL/DL) data).

FIG. 2B illustrates an example service request procedure. The numbersshown in FIG. 2B may be present for the purpose of the reference. Assuch, the numbered actions may be performed in a different order (e.g.,in whole or in part) that as shown in FIG. 2B. As seen in FIG. 2B, MTdata delivery may be performed (e.g., shown in numbered action 1). Asseen in FIG. 2B, a user plane between a WTRU and a RAN and/or between aRAN and a UPF may be established.

An evolved packet core (EPC) network may use IoT optimization. Forexample, in control plane IoT optimization, a WTRU and/or a network maydeliver UL/DL data through NAS signaling. FIG. 3 illustrates an examplecontrol plane IoT optimization. The numbers shown in FIG. 3 may bepresent for the purpose of the reference. As such, the numbered actionsmay be performed in a different order (e.g., in whole or in part) thatas shown in FIG. 3.

For example, in a user plane IoT optimization/inactive mode, a WTRUand/or a RAN may suspend a user plane. A WTRU and/or a RAN may suspend auser plane when the WTRU enters an idle mode and/or an inactive mode.If, for example, a WTRU has uplink (UL) data to deliver, the WTRU maysend a resume request message to the RAN (e.g., and/or skip signalingfor user plane establishment). The resume request message may bereferred to as a connection resume message and/or may be an RRC message.The RAN may resume the user plane.

User plane IoT optimization and/or inactive mode may support suspendingand/or resuming a user plane session that had been suspended. Theinactive mode may be transparent to a core network (e.g., the corenetwork may be unaware that the WTRU is in inactive mode and/or has asuspended user plane). FIG. 4 illustrates an example user plane suspendprocedure. The numbers shown in FIG. 4 may be present for the purpose ofthe reference. As such, the numbered actions may be performed in adifferent order (e.g., in whole or in part) that as shown in FIG. 4. Oneor more numbered actions shown in FIG. 4 may or may not be performed.For example, the suspend request, the release access bearer request andresponse, and/or the suspend response may be skipped for inactive mode.

FIG. 5 illustrates an example user plane resume procedure. The numbersshown in FIG. 5 may be present for the purpose of the reference. Assuch, the numbered actions may be performed in a different order (e.g.,in whole or in part) that as shown in FIG. 5. One or more numberedactions shown in FIG. 5 may or may not be performed. For example, aS1-AP resume message may not be sent for inactive mode.

A mobility management entity (MME) may use one or more different pagingstrategies. For example, a MME may use paging retransmission schemes,determining whether to send a paging message to the eNodeBs during a MMEhigh load condition(s). A MME may use one or more different pagingstrategies for a downlink (DL) NAS with data and/or a DL NAS withsignaling (e.g., PDU session modification request). In an EPC network, aMME may store a session management context and/or a mobility managementcontext. Storing a session management context and/or a mobilitymanagement context by a MME may allow the MME to determine pagingstrategies. In examples, in 5G core (5GC), an AMF may have sessioninformation. In examples, in 5GC, an AMF may not have sessioninformation. For example, in 5GC, an AMF may not have sessioninformation to determine paging strategies.

A WTRU may expect to release a NAS signaling connection to enter an idlestart. This may occur after completing a transaction (e.g., eachtransaction) with an IoT server. In an EPC network, a WTRU may indicateto a MME that there may be DL data (e.g., further expected DL data). Inexamples, the MME may release a NAS signaling connection. In examples,the MME may not release a NAS signaling connection based on theindication from the WTRU and/or session management state (e.g., DL databuffering). In examples, in 5GC, an AMF may have session information. Inexamples, in 5GC, an AMF may not have session information. For example,in 5GC, an AMF may not have session information to determine whether ornot to release a NAS signaling connection.

A WTRU may support control plane IoT optimization and/or may use a userplane to deliver data. For example, the WTRU may use the user plane todeliver data (e.g., a large amount of data).

A WTRU may enter an inactive state. If a WTRU enters an inactive state,a RAN may not notify a 5GC network that the WTRU is in the inactivestate. A SMF may release the user plane by a CN-initiated deactivationof the UP connection procedure. A SMF may release a PDU session. Forexample, the PDU session may be released if a PDU session is inactivefor a period. The period may be pre-configured. If the WTRU is in theinactive state and the 5GC (e.g., SMF, AMF, and/or the like) releases aPDU session, the PDU session context(s) stored in a RAN and/or a networkmay not match the PDU session contexts stored in the WTRU.

A serving/anchor RAN may receive a NAS signaling. The NAS signaling mayinclude IoT data. When the serving/anchor RAN receives a NAS signalingand/or finds that the WTRU is in RRC_INACTIVE state, the serving/anchorRAN may buffer the NAS signaling and/or page the WTRU. Paging may occurin the RAN paging area associated with the WTRU. The WTRU may receivethe paging and/or may access the RAN. For example, the WTRU may receivethe paging and/or may access the RAN to resume its RRC connection. Whenthe WTRU receives the paging and/or accesses the RAN, the WTRU mayaccess the serving/anchor RAN and/or the WTRU may access another RAN.The WTRU may access another RAN if, for example, the WTRU roams awayfrom the serving/anchor RAN. The RAN (e.g., current RAN) may retrievethe WTRU context and/or the buffered NAS signaling, which may includethe IoT data, from the anchor RAN. The new RAN may become a serving RAN.The serving RAN may initiate a N2 path switch procedure towards the CN.If, for example, there is no on-going user plane traffic and/or if thereis no active PDU session, the WTRU may not remain in a RRC_CONNECTED.The WTRU may be put back to a RRC_INACTIVE state. When the WTRU is pagedfor control plane (CP) data, the WTRU may have roamed to another RAN(e.g., another new RAN). The N2 path switch and/or related CNsignaling/procedure may serve a previous RAN (e.g., before the WTRUroamed to another new RAN).

A serving RAN change and/or N2 path switch may occur during mobileoriginated (MO) data delivery. If, for example, a WTRU sends a smallamount data for the UL and/or the WTRU does not expect a large amount ofdata to follow, the WTRU may switch to an inactive state. A serving RANchange and/or N2 path switch may be skipped (e.g., may not occur).

A SMF may indicate to an AMF that DL NAS signaling may be used for DLdata and/or signaling. The AMF may make one or more paging strategiesbased on the indication from the SMF.

FIG. 6 illustrates an example NW-initiated service request procedure.The numbers shown in FIG. 6 may be present for the purpose of thereference. As such, the numbered actions may be performed in a differentorder (e.g., in whole or in part) that as shown in FIG. 6. As seen inFIG. 6, a SMF may include DL data into N1 session management (SM)information, which may be indicated by a data indication within the N11message. An AMF may determine that the N11 message received from SMF isrelated to a NAS for data delivery. The AMF may make one or more pagingstrategies, which may be according to the data indication within the N11message. The AMF may send one or more paging messages to a RAN. The RANmay perform paging. For example, the RAN may perform paging to a WTRU. Adata over NAS indication may be included in the paging request message.A WTRU may respond to the paging from the RAN. For example, the WTRU maysend a service request to the RAN. The RAN may forward the servicerequest from the WTRU to the AMF. The AMF may include the N1 SMinformation in the DL NAS (e.g., service accept). The AMF may include adata indication in a N2 request message. The RAN may schedule the radioresource for DL NAS, which may be based on the data indication in the N2request message. A NAS message with user data and/or a NAS message forsignaling may have different priorities when congestion occurs in a RAN.The NAS messages (e.g., the NAS message user data and the NAS messagefor signaling) may use a control plane (CP) resource. The RAN mayforward the DL NAS to the WTRU.

The procedure of FIG. 6 may be used when the WTRU is in a RRC inactivestate. For example, an AMF may include a data over NAS indication to aRAN, e.g., in a N2 message. The RAN may determine a paging policy forRAN based paging in a RRC_Inactive scenario (e.g., based on the dataover NAS indication).

In examples, a WTRU may indicate to an AMF that there may or may not befurther DL NAS signaling. A SMF may indicate to the AMF that there maybe suspended DL NAS signaling and/or data for the WTRU. The AMF maydecide to release a NAS signaling connection. For example, the AMF maydecide to release a NAS signaling connection if there is no DL NAS fromthe WTRU (e.g., no expected DL NAS from the WTRU) and/or there is no asuspended DL NAS from the SMF.

FIG. 7 illustrates an example NAS signaling connection release. Thenumbers shown in FIG. 7 may be present for the purpose of the reference.As such, the numbered actions may be performed in a different order(e.g., in whole or in part) that as shown in FIG. 7. As seen in FIG. 7,NAS signaling connection release may be based on an indication from aWTRU and/or a SMF. For example, a WTRU may send a service request to aRAN. The service request may include N1 SM information (e.g., UL data)and/or may indicate there may not be further DL NAS. The RAN may sendthe service request to an AMF. In examples, the service request from theRAN to the AMF may include N1 SM information (e.g., UL data) and/or mayindicate there may not be further DL NAS. The AMF may send a N11 messageto a SMF, which may include N1 SM information (e.g., UL data). The SMFmay send a N11 message to the AMF. For example, the SMF may indicate tothe AMF that there may not be a suspended DL NAS from the SMF. The SMFmay indicate to the AMF that there may not be buffered NAS signalingand/or DL data. The AMF may determine to release the NAS connection(e.g., WTRU context), e.g., based on the received information from theSMF. The AMF may collect the indications (e.g., messages 1, 2, and/or 4of FIG. 7). The indication may be used to determine whether to release aNAS connection. For example, a NAS connection may be released if theWTRU does not expect a DL NAS and/or if there is not a suspended NASfrom a SMF (e.g., any SMF). The AMF may send a N2 WTRU context releasecommand to the RAN. The RAN may release the related RRC connection. TheRAN may send a completion message to the SMF.

In examples, a WTRU may indicate to a SMF that there may or may not befurther DL data (e.g., further expected DL data). The SMF may indicateto an AMF that there may not be further NAS signaling. This indicationmay be based on the indication from the WTRU and/or local information.For example, local information may include suspended DL NAS, buffered DLdata, and/or the like. The AMF may decide to release the NAS signalingconnection. For example, the AMF may decide to release the NAS signalingconnection if there is no further NAS signaling.

FIG. 8. Illustrates an example NAS signaling connection release. Thenumbers shown in FIG. 8 may be present for the purpose of the reference.As such, the numbered actions may be performed in a different order(e.g., in whole or in part) that as shown in FIG. 8. As seen in FIG. 8,the NAS signaling connection release may be based on an indication froma SMF. For example, a WTRU may send a service request to a RAN. Theservice request may include N1 SM information (e.g., UL data and/or a DLdata indication). The indication may be sent in a SM container, whichmay be transparent to the AMF. The RAN may send service requests to theAMF. The AMF may send a N11 message to a SMF, which may include N1 SMinformation (e.g., UL data and/or a DL data indication). In examples,the SMF may determine that there may be further NAS signaling. Inexamples, the SMF may determine that there may not be further NASsignaling. For example, the SMF may determine that there is no furtherNAS signaling based on one or more of the following: an indication fromthe WTRU indicating that there is no further DL data; the SMF having nobuffered DL data; signaling based on the received indication from theWTRU in the SM message; and/or its own determination that there may bepending DL signaling and/or data for the WTRU. If, for example, the SMFdetermines that there may be no further NAS signaling, the SMF mayindicate that determination to the AMF. For example, the SMF mayindicate to the AMF that there may not be further NAS signaling for theWTRU. The AMF may determine to release the WTRU context. For example,the AMF may determine to release the WTRU context, for example, if thereis no further NAS signaling from the SMF and/or any SMF. The AMF maysend a N2 WTRU context release command to the RAN. The RAN may release arelated RRC connection. The RAN may send a completion message to theSMF.

A WTRU may send a request to a SMF to deactivate a user plane (UP)connection and/or may indicate a switch to control plane IoToptimization. FIG. 9 illustrates an example WTRU-initiated deactivationof a UP connection. The numbers shown in FIG. 9 may be present for thepurpose of the reference. As such, the numbered actions may be performedin a different order (e.g., in whole or in part) that as shown in FIG.9. As seen in FIG. 9, a WTRU may trigger a WTRU-initiated deactivationof a UP connection. For example, a WTRU may trigger a WTRU-initiateddeactivation of a UP connection by transmitting a NAS message. The NASmessage may include N1 SM information, a UP deactivation request, and/ora PDU session ID. The UP deactivation request may include a controlplane (CP) optimization indication. The UP deactivation request mayinclude a CP optimization indication if, for example, a CP (e.g., NAS)is used for future data delivery. An AMF may determine if, for example,a SMF is impacted by the UP deactivation request. The determination ofAMF to identify a SMF impacted by the UP deactivation request may bebased on the PDU session ID. The AMF may send a N11 message to the SMF.The N11 message may include N1 SM information, a UP deactivationrequest, and/or a PDU session ID.

The SMF may determine whether or not to accept the UP deactivationrequest from the WTRU. For example, the SMF may determine to accept theUP deactivation request from the WTRU based on a configuration and/or auser subscription. The SMF may notify a UPF to remove RAN tunnelinformation. The SMF may forward the UP deactivation request indicationto the UPF. In examples, the SMF may forward the UP deactivation requestindication to the UPF to inform the UPF that data for the connection maybe transferred over a N4 interface. In examples, the SMF may forward theUP deactivation request indication to the UPF to inform the UPF thatdata for the connection may not be transferred over a N3 interface.

The UPF may determine not to release the network layer address (e.g.,IPv4 address, IPv6 prefix, and/or any non-IP address) for the WTRU. TheUPF may determine not to release the network layer address for the WTRU,e.g., based on the UP deactivation request indication. The UPF may storeother WTRU contexts. For example, the UPF may store other WTRU contexts,such as quality of service (QoS) rules and/or the like for the sessionassociated with the WTRU.

The SMF may send a N11 message. The N11 message may include a N2 SMsession release request. The N11 message, including a N2 SM sessionrelease request, may be a request to release RAN resources. The RANresources may be associated with a PDU session. The AMF may forward thereceived N2 SM session release request to a RAN. The RAN may issueaccess network (AN) specific signaling exchanges with the WTRU. Forexample, the RAN may issue AN-specific signaling exchanges with the WTRUto release the user plane resources of the RAN, which may be associatedwith the PDU session.

The SMF may acknowledge the UP deactivation request, e.g., by NASsignaling. The WTRU may keep the PDU session context and/or may use thesame PDU session ID in the NAS SM message when the WTRU sends data overNAS (e.g., a NAS SM message). For example, the WTRU may send data overNAS after receiving acknowledgement (e.g., NAS acknowledgement) from theSMF. The RAN may acknowledge the N2 session release request, forexample, by sending a N2 PDU session response to the AMF. The AMF maysend a N11 message, for example, to acknowledge the SM request receivedfrom the SMF.

A SMF may deactivate the user plane and/or determine to switch tocontrol plane IoT optimization. FIG. 10 illustrates an exampleCN-initiated deactivation of a UP connection. The numbers shown in FIG.10 may be present for the purpose of the reference. As such, thenumbered actions may be performed in a different order (e.g., in wholeor in part) that as shown in FIG. 10. As seen in FIG. 10, a SMF maydetermine to deactivate a UP connection of a PDU session. For example,the SMF may determine that a PDU session may be deactivated and/or CPoptimization may be used. The SMF may determine to switch to CPoptimization for future data delivery. For example, the determination toswitch the SMF to CP optimization for future data delivery may be basedon, for example, no data activity for a configured period and/or a WTRUsupporting CP optimization.

The SMF may notify a UPF to remove RAN tunnel information. The SMF mayforward a UP deactivation request indication to the UPF. In examples,the SMF may forward a UP deactivation request indication to the UPF toinform the UPF that data for this connection may be transferred over aN4. In examples, the SMF may forward a UP deactivation requestindication to the UPF to inform the UPF that data for this connectionmay not be transferred over a N3 interface. The UPF may determine not torelease the network layer address (e.g., IPv4 address, IPv6 prefixand/or a non-IP address) for the WTRU. The determination not to releasethe network layer address for the WTRU may be based on the UPdeactivation request indication. The UPF may store a WTRU context (e.g.,QoS rules and/or the like) for a WTRU session.

A SMF may send a N11 message. The message may include a N2 SM sessionrelease request and/or N1 SM information (e.g., CP optimizationindication). The N2 SM session release request may release RANresources, which may be associated with a PDU session. N1 SM informationthat includes a CP optimization indication, may indicate to a WTRU thatfuture data delivery may use the control plane (e.g., NAS signaling).The WTRU may deliver data using the control plane.

An AMF may forward a N2 SM session release request and/or a NAS messageto a RAN. For example, an AMF may forward a N2 message that may includeN1 SM information. The N1 SM information may include a CP optimizationindication.

A RAN may issue an access network (AN) specific signal to a WTRU. Forexample, the AN-specific signal may release RAN resources associatedwith a PDU session. The RAN may forward a NAS message to the WTRU. TheNAS message may include a PDU session ID. The WTRU, upon receiving theNAS message, may keep a PDU session context and/or may use the PDUsession ID when it sends data over NAS (e.g., a NAS SM message). TheWTRU may use NAS signaling to send data to the network. For example, theWTRU may use NAS signaling to send data to the network if the WTRU hasuplink data for the received PDU session ID. The RAN may acknowledge theN2 session release request. For example, the RAN may acknowledge the N2session release request by sending a N2 PDU session response to the AMF.

The AMF may send an N11 message. The N11 message may acknowledge a SMrequest from an SMF. An example message is illustrated in message 7 ofFIG. 10.

A RAN may remove UP resource locally. For example, a RAN may remove UPresource locally without notifying a WTRU. If, for example, the WTRU isinactive, a RAN may remove UP resource locally without notifying a WTRUduring a CN-initiated deactivation of a UP connection and/or a PDUsession release procedure. A WTRU may attempt to resume a connectionwith the RAN. The RAN may indicate a confirmation. For example, the RANmay indicate a confirmation by sending the resumed PDU session IDs tothe WTRU. The confirmation may indicate, to the WTRU, the PDU sessionsthat are resumed. For example, the confirmation may indicate, to theWTRU, the PDU sessions that are resumed by sending a synchronizationindication to the WTRU. Sending a synchronization indication to the WTRUmay trigger a registration procedure and/or a service request procedure,which may synchronize the PDU session state with the network.

FIG. 11A illustrates an example PDU session context synchronization. Thenumbers shown in FIG. 11A may be present for the purpose of thereference. As such, the numbered actions may be performed in a differentorder (e.g., in whole or in part) that as shown in FIG. 11A. As seen inFIG. 11A, a PDU session context synchronization may be done during aresume procedure. For example, a SMF may deactivate a UP connection of aPDU session and/or release a PDU session. The SMF may notify a UPF toremove RAN tunnel information. The SMF may notify the UPF to removetunnel resource(s) and/or context(s) with a N4 session. The SMF may senda N11 message, which may include a N2 SM session release request and/ora PDU session release command. The N2 SM session release request may bea request to release the RAN resources associated with a PDU session.

An AMF may forward the N2 SM session release request and/or a PDUsession release command to a RAN. The AMF may include an indication tothe RAN. For example, the AMF may include an indicator (e.g., skipindicator), which may indicate to the RAN to locally deactivate a UPresource. An indicator (e.g., a skip indicator) may inform the RAN tolocally deactivate a UP resource if a WTRU is in RRC_Inactive state. Anindicator (e.g., a skip indicator) may inform the RAN to locallydeactivate a UP resource without notifying a WTRU. For example, the RANmay deactivate UP resources without notifying the WTRU, if the WTRU isin RRC_Inactive state. The RAN may remove UP resources locally. The RANmay remove UP resources locally without notifying a WTRU. For example,the RAN may remove UP resources locally if the WTRU is in RRC_Inactivestate.

A RAN may acknowledge a N2 session release request, for example, bysending an N2 PDU session response to an AMF. The AMF may send a N11message to acknowledge the SM session release request.

A WTRU may establish one or more PDU sessions via a RAN node. A WTRU maytransition into an inactive state. For example, the WTRU may transitioninto an inactive state after establishing one or more PDU sessions via aRAN node. A WTRU may attempt a connection resume procedure (e.g., fromthe inactive state), e.g., via resume connection message. For example,the WTRU may provide a resume ID to a RAN. The RAN may use the providedresume ID, for example, to access the stored context associated with theWTRU.

The RAN may send an acknowledgement to the WTRU. In examples, the RANmay send an acknowledgement to the WTRU that the WTRU has entered aradio resource control (RRC) connected state. The RAN may indicate aresumed PDU session(s). In examples, the RAN may indicate a resumed PDUsession(s) by sending the resumed PDU session ID(s) to the WTRU. Inexamples, the RAN may send a message to the WTRU. The message mayindicate a subset of the one or more PDU sessions that are availablewhen the WTRU resume connection with the RAN. The RAN may indicate, tothe WTRU, to perform a PDU session synchronization with a core network(e.g., AMF and/or SMF). The RAN may indicate, to the WTRU, to perform aPDU session synchronization with the core network if a skip indicator isreceived.

In examples, the RAN may indicate, to the WTRU, a removed PDUsession(s). For example, the RAN may indicate, to the WTRU, a removedPDU session(s) by sending the WTRU the removed PDU session ID(s). Inexamples, the RAN may indicate active data radio bearers (DRBs) to aWTRU. In examples, the RAN may not indicate active DRBs to a WTRU. Forexample, if the WTRU receives a message from the RAN (e.g., message 9 ofFIG. 11A), which does not include DRB information associated with aremoved PDU session, the WTRU may deactivate the PDU session. Forexample, the WTRU may locally deactivate the PDU session (e.g., as shownin message 10 of FIG. 11A).

A WTRU may deactivate (e.g., remove) one or more UP resources that arenot resumed. For example, a WTRU may remove one or more UP resourcesthat are not resumed based on an indication from the RAN. The WTRU maydeactivate one or more established PDU sessions of the plurality of PDUsession. For example, the WTRU may deactivate one or more establishedPDU sessions of the plurality of PDU session based on the message fromthe RAN. As described herein, the message from the RAN indicates thesubset of the plurality of PDU sessions that are available.

The WTRU(s) may transition to an idle state. The WTRU may perform aregistration procedure and/or a service request procedure with thenetwork. For example, the WTRU may perform a registration procedure(e.g., new registration procedure) and/or a service request procedure(e.g., a new service request procedure) with the network if, forexample, the WTRU determines to perform a PDU session synchronization.For example, the registration procedure and/or the service requestprocedure may synchronize the PDU session states with the network.

A RAN may remove UP resource locally. For example, a RAN may remove UPresource locally without notifying a WTRU. If, for example, the WTRU isinactive, a RAN may remove UP resource locally during a PDU sessionrelease procedure. A WTRU may request to resume a connection with a RAN.The RAN may acknowledge the request from the WTRU and/or may resume theconnection with the WTRU. The RAN may indicate, to the WTRU, that theconnection has been resumed. For example, the RAN may send the WTRU theresumed PDU session ID(s). The RAN may indicate, to the WTRU, to performa PDU session synchronization with a core network (e.g., AMF and/or SMF)as described herein.

FIG. 11B illustrates an example PDU session context synchronization. Thenumbers shown in FIG. 11B may be present for the purpose of thereference. As such, the numbered actions may be performed in a differentorder (e.g., in whole or in part) that as shown in FIG. 11B. As seen inFIG. 11B, a PDU session context synchronization may be done after aresume procedure. For example, a PDU session release may occur (e.g.,after resume procedure). A SMF may decides to release a PDU session. TheSMF may notify a UPF to remove one or more (e.g., all) tunnelinformation and/or the N4 context. The SMF may send a N11 message. TheN11 message may include a N2 SM session release request and/or N1 SMinformation (e.g., a PDU session release command).

An AMF may forward the N2 SM session release request and/or the N1 SMinformation to a RAN. The AMF may include an indication. For example,the indication may be a skip indicator. The indicator (e.g., skipindicator) may indicate, to the RAN, to locally release an AN resource.For example, the indicator (e.g., skip indicator) may indicate, to theRAN, to locally release an AN resource without notifying a WTRU. Theskip indicator may indicate, to the RAN, to locally release an ANresource if, for example, the WTRU is in an RRC_Inactive state. The RANmay remove the AN resource. For example, the RAN may remove the ANresource without notifying the WTRU. For example, the RAN may remove theAN resource without notifying the WTRU if the WTRU is in a RRC_Inactivestate. The RAN may acknowledge the N2 session release request, forexample, by sending an N2 PDU session response to the AMF. The AMF maysend a N11 message. The N11 message may acknowledge the SM received fromthe SMF.

A WTRU may establish one or more PDU sessions via a RAN node. A WTRU maytransition into an inactive state. For example, the WTRU may transitioninto an inactive state after establishing one or more PDU sessions via aRAN node. The WTRU may attempt a connection resume procedure (e.g., fromthe inactive state). The WTRU may send a resume connection message(e.g., via RRC message) to a RAN node. For example, the WTRU may providea resume ID to a RAN node, e.g., via a resume connection message. TheRAN may use the provided resume ID, for example, to access the storedcontext associated with the WTRU.

The RAN node (e.g., or RAN) may acknowledge to the WTRU that the WTRUhas entered a radio resource control (RRC) connected state. The RAN mayindicate, to the WTRU, to perform synchronization with the core network.For example, the RAN node may send an acknowledgement to the WTRU. Inexamples, the RAN may send an acknowledgement to the WTRU that the WTRUhas entered a radio resource control (RRC) connected state. The RAN mayindicate a resumed PDU session(s). In examples, the RAN may indicate aresumed PDU session(s) by sending the resumed PDU session ID(s) to theWTRU. In examples, the RAN may send a message to the WTRU. The messagemay indicate a subset of the one or more PDU sessions that are availablewhen the WTRU resume connection with the RAN. The RAN may indicate, tothe WTRU, to perform a PDU session synchronization with a core network(e.g., AMF and/or SMF). The RAN may indicate, to the WTRU, to perform aPDU session synchronization with the core network if a skip indicator isreceived.

In examples, the RAN may indicate, to the WTRU, a removed PDUsession(s). For example, the RAN may indicate, to the WTRU, a removedPDU session(s) by sending the WTRU the removed PDU session ID(s). Inexamples, the RAN may indicate active data radio bearers (DRBs) to aWTRU. In examples, the RAN may not indicate active DRBs to a WTRU. Forexample, if the WTRU receives a message from the RAN (e.g., message 9 ofFIG. 11B), which does not include DRB information associated with aremoved PDU session, the WTRU may deactivate the PDU session. Forexample, the WTRU may locally deactivate the PDU session (e.g., as shownin message 10 of FIG. 11B).

A WTRU may deactivate (e.g., remove) one or more UP resources that arenot resumed. For example, a WTRU may remove one or more UP resourcesthat are not resumed based on an indication from the RAN. The WTRU maydeactivate one or more established PDU sessions of the plurality of PDUsession. For example, the WTRU may deactivate one or more establishedPDU sessions of the plurality of PDU session based on the message fromthe RAN. As described herein, the message from the RAN indicates thesubset of the plurality of PDU sessions that are available.

The WTRU(s) may transition to an idle state. The WTRU may perform aregistration procedure and/or a service request procedure with thenetwork. For example, the WTRU may perform a registration procedure(e.g., new registration procedure) and/or a service request procedure(e.g., a new service request procedure) with the network if, forexample, the WTRU determines to perform a PDU session synchronization.For example, the registration procedure and/or the service requestprocedure may synchronize the PDU session states with the network.

A RAN may remove UP resource locally. For example, a RAN may remove UPresource locally without notifying a WTRU. If, for example, the WTRU isinactive, a RAN may remove UP resource locally during a PDU sessionrelease procedure. A WTRU may request to resume a connection with a RAN.The RAN may acknowledge the request from the WTRU and/or may resume theconnection with the WTRU. The RAN may indicate, to the WTRU, that theconnection has been resumed. For example, the RAN may send the WTRU theresumed PDU session ID(s). The RAN may indicate, to the WTRU, to performa PDU session synchronization with a core network (e.g., AMF and/or SMF)as described herein.

The WTRU may perform a registration procedure and/or a service requestprocedure. For example, the WTRU may perform a registration procedureand/or a service request procedure to synchronize the PDU session stateswith the network. The WTRU may perform a registration procedure and/or aservice request procedure based on the received indication (e.g., asshown in message 10 of FIG. 11B).

FIG. 12 illustrate an example procedure for avoiding a service RANchange and/or N2 path switch. The numbers shown in FIG. 12 may bepresent for the purpose of the reference. As such, the numbered actionsmay be performed in a different order (e.g., in whole or in part) thatas shown in FIG. 12.

NAS signaling for mobile terminated (MT) data delivery and/or DL datavia user plane may be received and/or buffered at a serving/anchor RAN(e.g., as shown in FIG. 12). For example, DL data may be received from acore network (CN), e.g., via NAS signaling and/or via user plane, and/orbuffered at a serving/anchor RAN when DL data exists and/or a targetWTRU is in RRC_INACTIVE state. The serving/anchor RAN node may bufferthe DL data (e.g., received via the NAS signaling and/or via userplane). The serving/anchor RAN may page the WTRU. The WTRU may be pagedwhen the WTRU is in the paging area of the RAN. If, for example, theWTRU is within the paging area of the RAN, the WTRU may access the RANto resume RRC connection.

A WTRU may access a serving/anchor RAN to resume a RRC connection. Theserving/anchor RAN may forward a buffered DL data (e.g., received viaNAS signal or NAS message and/or via user plane) to the WTRU. Forexample, the serving/anchor RAN may forward a buffered DL data, receivedvia NAS signal and/or via user plane, to the WTRU in a RRC messageduring the connection resume procedure.

A WTRU may access another RAN (e.g., a new RAN) if, for example, theWTRU has roamed away from the serving/anchor RAN. The other RAN (e.g., anew RAN) may retrieve the WTRU context and/or a buffered NAS messagefrom the serving/anchor RAN. The other RAN (e.g., new RAN) may retrievethe WTRU context and/or buffered NAS message the serving/anchor RAN byderiving the information about the serving/anchor RAN from the RRCresume request (e.g., as shown in message 4 in FIG. 12). The resume IDmay include information about the serving/anchor RAN, such as servingRAN ID. The other RAN (e.g., a new RAN) may forward the DL data (e.g.,received via NAS message and/or via user plane) to the WTRU. Forexample, the other RAN (e.g., a new RAN) may forward the DL data (e.g.,received via NAS message and/or via user plane) to the WTRU in a RRCmessage during the connection resume procedure. The other RAN (e.g., anew RAN) may determine whether to become the serving RAN for the WTRU.The other RAN (e.g., a new RAN) may make this determination based on oneor more of the followings. In examples, if the WTRU context indicatesthere are no active PDU session, the other RAN (e.g., new RAN) maydetermine not to become a new serving/anchor RAN. In examples, if thenew RAN (e.g., other RAN) receives an indication from the serving/anchorRAN (e.g., serving/anchor RAN that the WTRU was previously connected to)that the new RAN may not become the new serving/anchor RAN, the otherRAN/new RAN may not become the new serving/anchor RAN. The other RAN(e.g., a new RAN) may receive the indication from the serving/anchorRAN, for example, by Xn signaling. In example, if a WTRU indicates in aRRC message (e.g., a resume request) that the WTRU may be in anon-allowed and/or forbidden, the other RAN (e.g., a new RAN) may notbecome a new serving/anchor RAN.

A WTRU may indicate to a new RAN that the resume procedure is triggeredfor small data delivery. For example, a WTRU may indicate to a new RANthat a large data may not be transferred and/or the WTRU may soon switchto an inactive state (e.g., after receiving the small data delivery).The new RAN may determine not to become (e.g., change to) a new servingRAN as described herein and/or may not perform (e.g., skip) a N2 pathswitch. For example, if a new RAN determines not to become a new servingRAN for a WTRU as described herein, the new RAN may not initiate a N2path switch. The new RAN may indicate this determination to aserving/anchor RAN of the WTRU (e.g., serving/anchor RAN that the WTRUwas previously connected to). The new RAN may indicate to the WTRU thatthe new RAN is in a RRC_INACTIVE and/or RRC_IDLE state. For example, thenew RAN may indicate to the WTRU that the new RAN is in RRC_INACTIVEand/or RRC_IDLE state after the new RAN has completed forwarding data(e.g., small data) through a NAS message(s) and/or the user plane. Inexamples, the indication to go back to an INACTIVE state and/or theforwarding of the NAS messages may be combined in a RRC message (e.g., asingle RRC message). In examples, the indication to go back to anINACTIVE state and/or the forwarding of the NAS messages may not becombined in a RRC message (e.g., a single RRC message). The new RAN mayindicate, e.g., via Xn signaling, to the serving RAN of the WTRU thatthe WTRU is now back in a RRC_INACTIVE and/or RRC_IDLE state. The newRAN may indicate to the serving RAN of the WTRU that the serving RANassociated with the WTRU has not been changed.

The processes described above may be implemented in a computer program,software, and/or firmware incorporated in a computer-readable medium forexecution by a computer and/or processor. Examples of computer-readablemedia include, but are not limited to, electronic signals (transmittedover wired and/or wireless connections) and/or computer-readable storagemedia. Examples of computer-readable storage media include, but are notlimited to, a read only memory (ROM), a random access memory (RAM), aregister, cache memory, semiconductor memory devices, magnetic mediasuch as, but not limited to, internal hard disks and removable disks,magneto-optical media, and/or optical media such as CD-ROM disks, and/ordigital versatile disks (DVDs). A processor in association with softwaremay be used to implement a radio frequency transceiver for use in aWTRU, terminal, base station, RNC, and/or any host computer.

1-15. (canceled)
 16. A method comprising: receiving a first message froma network node, wherein the first message indicates an identification(ID) for a protocol data unit (PDU) session, wherein the network node isassociated with a radio access network (RAN); sending a deactivationindication to the network node, wherein the deactivation indicationindicates to deactivate a user plane (UP) connection associated with theID for the PDU session; receiving an indication from the network node,wherein the indication indicates to maintain a PDU session contextassociated with the ID for the PDU session; and transmitting data via acontrol plane (CP) using the maintained PDU session context.
 17. Themethod of claim 16, wherein to send the deactivation indication, themethod comprises: determining to send the deactivation indication todeactivate the UP connection based on an amount of data expected to betransmitted, wherein on a condition that the amount of data expected tobe transmitted is small, deactivate the UP connection and transmit thedata via the CP using the maintained PDU session context, and on acondition that the amount of data expected to be transmitted is large,maintain the UP connection and transmit the data using the ID for thePDU session.
 18. The method of claim 16, wherein the data transmittedvia the CP is smaller than data to be transmitted via the UP connection,and wherein the deactivation indication further indicates to switch fromthe UP connection to a CP connection.
 19. The method of claim 16,wherein the deactivation indication comprises at least one of adeactivation message, a non-access stratum (NAS) message, a UPdeactivation request, a PDU session ID, or a CP optimization indication.20. The method of claim 16, wherein to maintain the PDU session context,the method comprising: maintaining a network layer address associatedwith the PDU session.
 21. The method of claim 16, wherein the methodcomprises: transmitting the data via the CP using the same ID for thePDU session as the one used prior to deactivating the UP connection. 22.A network node comprising: a processor configured to: receive a firstmessage, wherein the first message indicates whether data is to beexpected; based on the received first message, determine whether torelease a non-access stratum (NAS) connection; and based on adetermination to release the NAS connection, send a second message,wherein the second message indicates that the NAS connection is to bereleased.
 23. The network node of claim 22, wherein the network nodecomprises an access and mobility management function (AMF).
 24. Thenetwork node of claim 22, wherein the first message is a NAS message.25. The network node of claim 22, wherein the first message is receivedfrom a wireless transmit/receive unit, and wherein the first messagefurther indicates N1 SM information.
 26. The network node of claim 22,wherein the first message is received from a service management function(SMF), and wherein the first message further comprises a N11 message.27. The network node of claim 22, wherein the first message indicatesthat further downlink NAS signaling is not expected or further downlinkdata is not expected.
 28. The network node of claim 22, wherein thesecond message is sent to a radio access network node.
 29. A methodcomprising: receiving a first message, wherein the first messageindicates whether data is to be expected; based on the received firstmessage, determining whether to release a non-access stratum (NAS)connection; and based on a determination to release the NAS connection,sending a second message, wherein the second message indicates that theNAS connection is to be released.
 30. The method of claim 29, whereinthe method is performed by a network node, wherein the network nodecomprises an access and mobility management function (AMF).
 31. Themethod of claim 29, wherein the first message is a NAS message.
 32. Themethod of claim 29, wherein the first message is received from awireless transmit/receive unit, and wherein the first message furtherindicates N1 SM information.
 33. The method of claim 29, wherein thefirst message is received from a service management function (SMF), andwherein the first message further comprises a N11 message.
 34. Themethod of claim 29, wherein the first message indicates that furtherdownlink NAS signaling is not expected or further downlink data is notexpected.
 35. The method of claim 29, wherein the second message is sentto a radio access network node.